The instant invention relates to inserting machines and more particularly to a vacuum block used in the document feeder for lifting and separating the front cover from the back cover of a booklet.
Inserting machines are used for assembling a plurality of sheet materials into a properly ordered packet and then inserting the ordered packet into a receptacle such as an envelope, a bag or a booklet located downstream thereof. In the case of a booklet having a front and a back cover comprising a relatively light material such as paper, it is necessary that the front and back covers be separated before the ordered packet can be nested within the front and back covers of the booklet. Heretofore, a typical approach for dealing with the need to separate the booklet covers involved the use of a separating bar. This approach required that the front cover of the booklet be wider than the back cover in order that the front cover, as it emerged from the feed rollers of the booklet feeder, would be prevented from falling to the transport deck therebelow. The back cover did fall to the transport deck since the booklet was fed to a point where the longer, front cover would be suspended by the separating bar while the shorter, back cover would pass and not be caught by the separating bar. In this position, with the front and back covers separated, the ordered packet of sheet materials which were assembled upstream are nested within the booklet located downstream.
The foregoing approach for separating booklet covers has worked well, but there is the drawback of the front and back covers of the booklet being of unequal width, which problem is overcome by the instant invention which separates the front and back covers of a booklet but which allows the front and back booklet covers to be of equal width.